1. Technical Field
This invention is related to the field of internal combustion (IC) engine ignition diagnosis systems. More particularly, it is related to the field of detecting ionization current in the combustion chamber of an IC engine and using the detected ionization signal to monitor ignition parameters and diagnose engine performance.
2. Discussion
The prior art includes a variety of conventional methods for detecting and using ionization current in a combustion chamber of an internal combustion engine. However, each of the various conventional systems suffers from a great variety of deficiencies. For example, prior art ionization current detection circuits are generally too slow and generate a current signal with low signal-to-noise ratio.
Internal Combustion Engine on-plug ignition coils with transistor drivers located in ECMs or other remote locations are prone to high electromagnetic interference emissions and are subject to interference from other components due to long connecting wires. Ionization detection circuits have even greater electromagnetic interference problems because of their very low signal current levels (microamperes).